incomplete1.c

gcc-you can use this code to learn something about gcc, and inquire further into linux,

// Build don't link:

// Copyright (C) 2000 Free Software Foundation, Inc.
// Contributed by Nathan Sidwell 28 Nov 2000 <[e-mail]>

// Inspired by by 756. We'd ICE when trying to define a member of an
// incomplete template type.

template<class X> struct ObjCount;  // ERROR - forward decl

template<class X> int ObjCount<X>::m; // ERROR - undefined type